Multicellular mobile radio systems are usually arranged in hierarchical structures. A telecommunications terminal such as a subscriber's mobile unit for example communicates in such systems with a base station, which takes over the radio coverage of a geographical area, a so-called radio cell. The base stations in their turn can be connected to switching centers, for example a communication system, which allows interworking with other communication networks. In the ideal case a radio cell with a hexagonal structure is covered by a base station, with the base station usually being positioned in the center of the cell. In reality however the embodiment of the network structure is influenced by the geographical topology, since height, landscape and architecture profile influence the wave propagation of a base station and thereby distort a regular structure.
Especially in buildings, such as production shops for example, where the architecture profiles heavily influence the wave propagation, radio coverage or suitable radio field illumination must be detected at regular intervals for the design and the checking of the mobile radio network, in order for example to prevent a fault or an interruption in a telecommunication connection, especially during what is known as a handover between two radio cells within a radio area or what is known as roaming between two areas consisting of a plurality of radio cells.
Usually this check on a suitable radio field illumination or radio coverage is performed manually in a multicellular mobile radio system with a metering unit developed specifically for the purpose. To put it more precisely, measuring crews use a mobile measuring device to at least make spot checks on the area to be covered by the multicellular mobile radio system, and if radio coverage is absent or is insufficient a correction of the mobile radio system is undertaken. Such a check must be repeated especially after changes to building or expansion of the multicellular mobile radio system in order to guarantee a sufficient radio field illumination, but this generates extraordinarily high costs.
A method is known from EP 1 398 910 A2 for automatic detection of a radio coverage in a multicellular mobile radio system. In this method a plurality of base stations are connected to a control unit, in which case all base stations are switched into a receive operating mode and a relevant field strength of locally adjacent base stations is measured. The measured field strength data is subsequently evaluated in an evaluation unit.